By way of review, an optical transceiver is an integrated fiber optic component including an optical transmitter and an optical receiver, which is capable of providing bi-directional transmission of data between an electrical interface and an optical data link. The optical transceiver receives and converts electrically encoded data signals into optical signals which are then transmitted over the optical data link. Likewise, the optical transceiver receives and converts optically encoded data signals into electrical signals and transmits the electrical signals in the electrical interface. Nowadays, for the requirement of handling data transmission in massive volume, miniaturization of this optical transceiver is desirable in order to maximize the available number of optical transceivers per area of a circuit board. Various standards are known that define form factors for miniaturized electronic devices, such as the Small Form-Factor Pluggable (SFP) standard that is the one most widely adopted and specifies an enclosure 9.8 millimeters in height by 13.5 millimeters in width and having a minimum of 20 electrical input/output connections.
Because the application of SFP enabling a plurality of optical transceivers to be consisted in a module which are hot-swappable and thus can be easily interchanged, not only the efficiency of data transmission is increased, but also electro-optical or fiber optic networks can be upgraded and maintained more conveniently than has been the case with traditional soldered-in optical transceivers. Rather than replacing an entire circuit board containing several soldered-in optical transceivers, a single SFP transceiver can be removed and replaced for repair or upgrading. This can result in a substantial cost savings, both in maintenance and in upgrading efforts.
Since it is desire to arranged a plurality of miniaturized optical transceivers in a module, it is necessary to consider how to properly configure the plural transceivers and what is the appropriate means for releasing the transceivers from the module as well. A poor configuration or poorly designed releasing means not only may worsen the manufacturing cost, but also can cause a certain maintenance difficulties, and more particularly, the poorly designed releasing means might cause the damage of the optical transceiver or the optical fiber connected thereto during an releasing process and thus affect the performance and life span of the optical transceivers.
As disclosed in the U.S. Pat. No. 6,364,709, entitled “Small Form-Factor Pluggable Transceiver Cage”, the pluggable cage uses a plurality spring tabs and a latch hole to hold the optical transceiver, and further utilizes the resilience force provided by bulge patches formed at the bottom of the cage for ejecting the optical transceiver while the same is disengaged from the plural spring tabs and the latch hole. Moreover, a cage structure similar to that of the U.S. Pat. No. 6,364,709 is disclosed in WO 03/098750 A1, entitled “Wire Lever Actuator Mechanism For Optical Transceiver”.
In addition, U.S. Pat. No. 6,434,015, entitled “Small Form-Factor Pluggable Module Having Release Device”, shows a cage for retaining a SFP module. The cage uses a spring tab formed at the frond end of the bottom of the cage to clasp to a triangular latch formed at the front of the SFP module such that the SFP module is fixed while a spring means arranged at the back panel of the cage is being compressed. Therefore, while releasing the SFP module, a push bar arranged at the front of the SFP module is pushed to release the triangular latch from the spring tab so that the resilience force of the compressed spring means can eject the SFP module.
From the above description, it is noted that most of the convention release devices for optical transceiver have shortcomings list as following:                (1) The ejection function performed by the spring means of the release device may fail due to elastic fatigue of the spring member, since the spring means may be compressed for a long period of time before releasing.        (2) The spring tab might block the way for obstructing the installation of the optical transceiver while the triangular latch is damaged or not functioning properly.        (3) The cracks of the spring tabs due to a finishing process might cause electromagnetic interference.        (4) A sufficient space is required at the back of the cage for allowing the disposition of the spring means.According, there is a need for an eject-lever apparatus for an optical transceiver capable of solving the abovementioned shortcomings.        